Currently, various types of foamed product and the like are used as heat insulating materials or the like for cold insulation of a cold insulation container. As such foamed products, for example, there is known a foamed product composed of paper powder component or plant powder component of 10 to 40% by weight, starch component of 25 to 40% by weight as auxiliary agent, and polypropylene component of 35 to 50% by weight (for example, refer to Patent Literature 1).
In such foamed product, used official postcards or used general paper is used for the paper powder component, and it is said that the foamed product can be incinerated as normal wastes after being used. Furthermore, by covering six internal surfaces of a box body such as a corrugated cardboard box or the like with the foamed product, a cold insulation space is obtained inside the box body, thereby enabling to obtain excellent cold insulating effect for the cold insulation space.